Batter Out of Box in MLB

[rbmartin]

When I'm behind the plate my primary job is balls & strikes. My secondary job is....balls & strikes.
Down the list at #58 is the batters position on the box when the pitch is delivered. At #87 is whether or not he may have stepped out of the box while making contact.
The main reason I even look at his feet is to make sure a batted ball doesn't hit one of them in the box (not always easy to see).
It's not something I am actively looking for and it I was, it would distract me from job #1....tracking the ball.